keel
/ki:l; kil/ n
1 timber or steel structure along the bottom of a ship, on which the framework is built up （船的）龙骨
lay down a keel, ie start building a ship 安龙骨（动工造船）.
2 (idm 习语) on an even keel => even1. keel, v (phr v) keel over
1 (of a ship) capsize （指船）倾覆, 翻倒.
2 (infml 口) fall over; collapse 倒下; 倒塌
After a couple of drinks he just keeled over on the floor. 他喝了两杯酒後就跌倒在地了.
The structure had keeled over in the high winds. 那座建筑物让大风给刮倒了.